Means and method for trimming blanks



July 15, 1924', 1,501,081 R.- L.IWIL COX MEANS AND METHOD FOR TRIMMING BLANKS FildJuly 1. 1 921 r ww 2 if "WV" Patented July. 15, 1924.

" STATES 1,501,081 PATENT OFFICE.

RICHARD LESTER WILCOX, OF WATERBURY, CONNECTICUT, ASSIGNOR TO THE WATER- BURY FARREL FOUNDRY AND MACHINE COMPANY, OF WATERBURY, CONNECTI- CUT, A CORPORATION O'F CONNECTICUT.

MEANS AND METHOD FOR TRIMMING BLANKS Application filed July 1, 1921. Serial no. 481,846.

To all whom it may concern:

Be it known that I, RICHARD LESTER lViLoox, a citizen of the United States, residing at Waterbury, in the county of New Haven and State of Connecticut, have invented certain new and useful Improvements in Means and Method fo Trimming Blanks,

of which the following isa specification, reference being had therein to the accompanying drawings.

This invention relates to means and method by which a blank may be given a polygonal cross-section such as the square, hexagonal or octagonal shapes of bolt heads, nuts and the like, or a many sided shape of any kind such, for instance, as a circular section with flat sides, as on shackle bolts and the like. It will be understood that by polygonal I mean any such shape.

It is the object of this invention, among other things, to give a trimmed cross-section to a blank by an entire cutting of the metal without tearing it and at the same time with the minimum amount of cutting pressure, a desirable advantage resulting therefrom being the production of a clean and unbroken cut surface on the blank.

As the trimming of bolt heads, nuts or the like has been heretofore carried out, the blank is forced through the die by a punch having the same size and shape in cross section as the opening in the die, or of slightly less dimensions. In any case the punch usually enters the die or is brought to a full stop exactly flush with its face. By such means and method the die cuts the blank until the resistance to the cutting pressure has been substantially overcome when the remaining excess metal is practically torn from the blank, leaving the face thereof rough and generally with depressions below what should be the finished face. In some classes of work bolts, nuts or the like thus formed are undesirable because of their unsightly and unfinished appearance.

I have found that trimming blanks with a very superior finish may be produced by supporting the surplus metal as it is formed by the cutting die and preventing the same from rolling away from the face of the die, and the means herein shown produce such desirable result.

In the drawing,

Figure 1 is a sectional view of the punch and Figure 5 is a fragmentary detailed view of the inner end of the supplemental punch.

Corresponding parts are referred to both in the drawing and specification by similar reference characters. I i

In the drawings 10 designates the die which is shown herein as having a hexagonal opening 11 therethrough which is preferably supported in a holder 12 and having a planishing die 13 in the rear thereof. This die is shown as having a face 14 that recedes slightly from the cutting edge 15 thereof, but it may be fiat if desired.

The punch 16 is supported in the holder 29 and mounted in a suitable moving part. Independently movable within the punch is the supplemental punch 17. Upon the operating face of the punch 16 is a punch ring 19 the edge 20 of which is slightly larger thancsaid opening 11, but may be flat for flat head blanks. As shown the ring .19 is annular, but it may be polygonal in form, as desired corresponding in form with the opening in the die, and therefore by ring I mean a form either round or polygonal.

The interior of the punch ring 19 has a cup face 18 as does also the outer end of the, supplemental punch 17 at 21 to correspond with thecurvature of the head of the blank.

As shown in Figure 1 the punches have a continuous unbroken contact with the entire surface of the head 22 of the blank, thus giving the maximum uniform pressure thereto for the cutting operation and eliminating the possibility of marring or marking the top of the finished head as is so frequently done in the mechanism now in common use. This cupping of the punches will be omitted, of course, if the head of the blank is flat.

In practice it is usual to have the .die 10 held stationary and the punch 16 movable and punch are of sufiicient distance apart to permit the placing therebetween of a blank 23 and as the punch then moves toward the die, the shank of the blank enters the quill 24 which supports and accurately centers the blank'in relation to the opening 11. During the forward movement of the punch the curved head of the blank rests in the cupped face of the punch and supplemental punch and the head of the blank, which is usually circular in cross-section before the beginning of the operation, is shaved by the die 10. The metal accumulated by this operation is folded back over the edge 20 of the punch ring 19 at a point slightly outside of the opening 11, thus permitting free flowing of the surplus metal as it is formed.

As the punch continues to force the blank into the die, any breaking off of the surplus metal is outside of the finished surface of the head 22 or, in other words, the blanks have a clean sheared surface the entire length of the head. This is facilitated by stopping the punch 16 a limited distance away from the face of the die 10, the pressure upon) the blank thereafter being applied by the supplemental punch 17. Thus when the surplus metal or chip breaks from the head of the blank the break is outside of the finished surface of the head and the limited amount of material left thereon is trimmed off '5 smoothly by the subsequent movement of the blank through the die by the pressure from the supplemental punch 17. This latter punch continues its movement until the head of the blank has passed entirely through the planishing die 13 which gives a high finish to the recently cut surace.

To prevent the blank from adhering to the end of the supplemental punch 17 when being withdrawn, I have inserted a plunger 25 in the end thereof which is moved outwardly by a spring 26 and prevented from disengagement by a pin 27 that passes through the punch and the slot 28 in the plunger.

As the supplemental punch is withdrawn, the pressure of the spring 26 against the I plunger 25 is sufficient to prevent the blank as the shape of from being withdrawn with said supplemental punch. In brief, to break the attraction th'erebetween that sometimes occurs.

The exterior shape of the punch and dies may, of course, be varied indefinitely as well plunger 25 and its actuating means may be omitted, if desired, and in these and many the opening in the die, the

ways my invention may be modified and I desire it to be understood that I do not limit myself to the exact construction herein shown and described, but claim all that falls fairly within the spirit and scope of the appended claims.

What I' claim as new and desirev to secure by Letters Patent isz 1. The described method of giving a trimmed cross section to a blank, consisting in forcing the blank beyond the cutting edge of a cutting die by first applying a pressure thereto over an area greater than that of the opening in the cutting die and then by pressure applied thereto over an area less than that of said opening, the flow of the metal during said cut being uninterrupted.

2. A die having an opening therethrough with cutting edges around the outer edge thereof, a punch, the axis of the die and punch being'coincident, and a supplemental punch movably mounted within said punch, the end of the punch and supplemental punch both being concaved to correspond substantially with the shape of the convex face of the head of the blank.

3. The described method of giving a trimmed cross-section to a blank, which consists in making a cut from the bottom to substantially the top of the blank, allowing the excess metal during the cutting operation to flow freely until the cut is adjacent to the top of the blank, during which time pressure is applied to the blank over an area greater than that of the opening in the cutting die and thereafter applying pressure to the blank over an area less than that of the area of said opening and at the same time limiting the space into which said excess metal may flow.

4. A die having an opening therethrough with cutting edges around the outer edge thereof, a punch having a ring formed upon the face thereof slightly larger than the opening through said die, the die and punch being so positioned relatively that the opening in the die is substantially concentric with the ring of the punch and a supplemental punch movably mounted within said punch, to move therewith and relatively thereto.

5. The described method of giving a trimmed cross-section to a blank, which consists in applying pressure substantially uniformly over one face of the blank and forcing it through an opening of less cross-sectional area than that of the surface to which pressure is applied as aforesaid and after said blank has been partially trimmed discontinuing some of the pressure so applied and continuing the trimming operation by the application of the remainder of the pressure applied to the blank over a much less area, the movement of the blank under the successive pressures being continuous.

6. A die having an opening therethrough I with cutting edges around the outer edge thereof, a punch having a ring formed upon the face. thereof slightly larger than the opening through said die, the die and punch i being so positioned relatively that the opening in the die is substantlally concentric with the ring of the punch, and a supplemental punch movably mounted within said punch of less diameter than said punch ring, that portion of the punch inside of said ring and the end of said supplemental punch both corresponding substantially with the shape offthe head of the blank. V

7. A die having an opening therethrough with cutting edges around the outer edge thereof, a punch having a ring formed upon the face thereof slightly larger than the opening through said die, the die and punch being so positioned relatively that the opening in the die is substantially concentric with the ring of the punch, and a supplemental punch movably mounted within said punch of less diameter than said punch ring, and

a stripper device connected with said supplemental punch for insuring the separation of the punch from the blank when the latter is being withdrawn therefrom.

8. A die having an opening therethrough with cutting edges around the outer edge thereof, a punch having a ring formed upon the face thereof slightly larger than the opening through said die, the die and punch being so positioned relatively that the opening in the die is substantially concentric with the ring of the punch, and a supplemental punch movably mounted within said punch of less diameter thansaid punch ring, and a stripper device, comprising a spring actuated member within said supplemental punch for insuring the separation of the punch from the blank when the latter is being withdrawn therefrom.

In testimony whereof, I have hereunto aflixed my signature.

' RICHARD LESTER WILCOX. 

